The band will play a free gig at Birthdays in Dalston tomorrow night (August 22).
The concert is in celebration of their latest album Four reaching number one in the midweek charts.
Bloc Party tweeted: "We just found out we are Number 1 on the midweek chart. We want to celebrate! Anyone up for a gig in London tomorrow night?
"Birthdays! London N16! Tomo! Free and first come first serve. 7:30 doors. 8:30 show."
Bloc Party's Kele Okereke recently revealed that the band's new album is heavily influenced by Nirvana.
"I was listening to a lot of Nirvana. I've never been that big a Nirvana fan, but I listened to Bleach a lot when we were making the record," he said.
"I was really impressed by how raw the whole thing was and how intentionally under-produced it was."
Watch Bloc Party's video for 'Octopus' below: